<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <style type="text/css">
        #p1{font-weight:lighter;}
        #p2{font-weight:normal;}
        #p3{font-weight:bold;}
        #p4{font-weight:bolder;}
    </style>
</head>
<body>
    <p id="p1">字体粗细为:lighter</p>
    <p id="p2">字体粗细为:normal</p>
    <p id="p3">字体粗细为:bold</p>
    <p id="p4">字体粗细为:bolder</p>
</body>
</html>